Present technology DAC devices store configuration information and input data in volatile memory. The configuration information and input data stored in the volatile memory are lost when operating power is removed from the DAC device and the associated volatile memory. For example, a DAC device may be used to output a programmable analog voltage. The programming bits, e.g., digital representation of the analog voltage, are stored in a DAC register which is volatile, thereby loosing its contents when powered down. Upon an initial power-up of the DAC device, the DAC register is either cleared or its contents are not predictable until the DAC register is programmed again. Thus the DAC register must be reprogrammed each time the DAC device is powered up. This necessitates additional program cycles of a master controller program so as to reprogram the DAC register. In many applications, DAC devices support operation of other devices in a system. For example, the DAC device may provide a reference voltage to other devices for proper operation thereof. Since the DAC register has to be reprogrammed, all other devices dependent upon the DAC device must wait (prevented from operating) until the DAC register contains the correct data.
DAC devices are becoming more prevalent in integrated circuits having both analog and digital functions, e.g., mixed signal devices. Typically, mixed signal devices (slaves) will communicate with a master device such as master control unit (MCU), e.g., microcontroller, microprocessor, digital signal processor, etc., over a communications bus. There may be more then one mixed signal slave device connected to the communications bus, thus each one of the mixed signal slave devices will need a device address. Generally the mixed signal device has either multiple address programming pins on the integrated circuit package, or the mixed signal device has a fixed address that is mask programmed during fabrication at the factory. For a three bit address, up to eight different integrated circuit fabrication masks are required. Having to mask program up to eight different addresses into mixed signal devices that are otherwise identical increases manufacturing time and costs, and results in having to stock and ship up to eight different parts. In addition, having mixed signal devices with non-field programmable addresses may become very inconvenient in certain applications.